Mirror mephit and simulacrum

[Waldham]

Is it possible for a mirror mephit to create a simulacrum of a advanced (10 HD) mephit mirror /Wizard 4 ?

So, the simulacrum has 7 HD.

If the the spell caster level for a simulacrum spell-like abilty from a mirror mephit is HD + 4.

Will the advanced mirror mephit/wizard 2 have a spell caster level of 11 th for simulacrum spell like ability ?

[Phelix-Mu]

SLA CL and CL from a Spellcasting class ability don't usually stack like that. Unless the mirror mephit entry specifies otherwise, the CL is fixed. Many creatures don't even advance SLA CLs when they advance racial HD either.